Sometimes Treatment Is Hard To Swallow

2048 is (PSPACE) Hard, but Sometimes Easy

We prove that a variant of 2048, a popular online puzzle game, is PSPACE-Complete. Our hardness result holds for a version of the problem where the player has oracle access to the computer player’s moves. Specifically, we show that for an n × n game board G, computing a sequence of moves to reach a particular configuration C from an initial configuration C0 is PSPACE-Complete. Our reduction is ...

Sometimes It’s Hard to Be Coherent

The paper provides an analysis of the construction in Hungarian known as focus raising, illustrated below. János-t mond-t-am hogy jön John-ACC say-PAST-1SG that come.3SG ‘It is John that I said is coming.’ In focus raising, the focus of the matrix clause is identified with a grammatical function in the embedded clause. Focus raising is particularly interesting because of the case marking on foc...

Easy Problems are Sometimes Hard

We present a detailed experimental investigation of the easy-hard-easy phase transition for randomly generated instances of satisfiability problems. Problems in the hard part of the phase transition have been extensively used for benchmarking satisfiability algorithms. This study demonstrates that problem classes and regions of the phase transition previously thought to be easy can sometimes be...

Finding an o(n2 log n) Algorithm Is Sometimes Hard

Switching to the Euro: still hard to swallow.